Dry shaving device



Dec. 2, 1941. 5 T. J. MURPHY DRY SHAVING DEVICE Filed July 3, 1937 2 She'Ls-SheefI 1 M .TVENTOR y M794 A TORNEYS.

DeC 2, 1941 T. J. MURPHY DRY rSHAVING DEVICE 2 Sheets-Sheet 2 Filed July 3, 1957 Fzgf/ )(lNvx-:NTOR

A ToRNEYs Patented Dec. 2, `1941 UNITED STATESV PATENT OFFICE X 2,264,398 DRY SHAVING DEVICE Thomas J. Murphy, Stamford, Conn.

Application July 3, 1937, Serial No. 151,813

12 claims. (o1. 3o-4s) This invention relates to new and useful improvements in shaving devices and particularly to a device of the type known as a dry shaver, such devices being adapted for use in the shaving operationwithout the aid of soap, cream, etc.v

A particular object of the invention is to pro-` vide an improved shaving device which will cut the hairs positively and rapidly close to the surface of the skin with a minimum of irritation of the skin.

Another object is to provide a construction which will permit the hairs to enter readily to the cutting position but will not permit entrance of the skin to an objectionable amount or degree and thus there will be no danger of cutting or objectionably irritating the skin.

A further object is to provide a device of this' type with which a clean, close shave may be easily and quickly secured, and in which the construction is such that danger of clogging of thereadily,

understood the invention is not limited to thedetails shown, but includes variations and modications falling within the spirit of the invention.

This device is of a type similar to the construction disclosed in my prior application Serial No;

'754,812 led November 26, 1934, which became Patent No. 2,146,643, February '7, 1939 land includes certain improvements tending to more satisfactory and eicient operation.

In these drawings:

Fig. 1 is a side elevation of a cutter head involving the invention with parts broken away to more clearly show the construction; Y

Fig. 2 is a partial end view looking from the right of Fig. 1 and a partial vertical section substantially on line 2-2 of Fig. 1, and on an en larged scale;

Fig. 3 is a top plan view of one end portion of the device of Fig. 1 on a still larger scale with parts broken away to more clearly show the construction;

Fig. 5 is a longitudinalvsection in a horizontal plane of one` end portion of the inner or movable cutter member substantially on line 5-5 of Fig. 2;

Fig. 6 is an enlarged view of a few of the cutter teeth on one side of the outer or stationary cutter member;

' Fig. 6a is a transverse section substantiallyv on line (iw-Ba of Fig. 6;

Fig. 7 is a side elevation of the mounting block of the outer or stationary guard members;

Fig. 8 is a top plan view of the right hand end of Fig. 7;

' Fig. 9 is an elevation of the upper end of one of the mounting members for the head on the actuator looking from the left of Fig. 1; Fig. 10 is a side elevation of a modication;

Fig. 11 is an end view thereof looking from the right of Fig.` and on an enlarged scale;

Fig. 12 is a top plan View of one end portion ofthe device of Fig. 10 on a still larger scale;

Fig. 13 is an end view similar to Fig. 11 showing a'slight modification.

element used in the device of Figs. 1, 2 and 3*;

It is to be understood that the devices are shown in the drawings on an enlarged scale so that the constructioncan be more clearly indicated, the actual devices used for shaving being considerably smaller than these drawings indicate.

Referring flrst to Figs. 1 to 9 inclusive the construction of the cutter head itself is shown with onlyI a portion of the mounting and operating means as the invention is directed primarily to the lconstruction of the cutter head.

'I'he device shown comprises a mounting block I 'on the opposite sides of which are mounted the outer stationary cutter elements 2 each having an inwardly directed row of cutter teeth 3. The elements 2 can be plates of proper thickness having laterally extending portions at their upper edges in which the teeth 3 are cut. It will be seen the block I holds the elements 2 in spaced relation and the rows of teeth 3 are also in' spaced relation, although extending toward each other so that the free ends of these teeth form the opposite sides of a longitudinal slot 0r space 4. Thel elements 2 may be mounted on the assembly block I by any suitable means but are preferably soldered thereto, and to facilitate this` the block may be provided with .shallow recesses 5 in the opposite sides thereof to receive solder 6 from which it may ow throughout the contacting surfaces between the block I and the elements 2 when heated. 'I'his V facilitates manufacturing and machining of the separate elements, and when assembled there is no danger of their shifting out of their relative positions. It will be noted that the outer surfaces I of the elements 2 and the teeth 3 are preferably inclined somewhat from the outer edges of the cutter head toward the space or slot l. Also, the inner surfaces of the teeth are more steeply inclined so that the teeth themselves and the supporting portion connecting them to the body of the elements 2 are tapered, making them thicker toward the body of the element so that although the free ends of the teeth are very thin so that the hairs may be cut close to the surface of the skin, still the teeth are strong and rigid and are self supporting and will not yield under pressure of the device against the surface of the skin during the shaving operation. The slots or grooves 3a between the teeth are flared outward as indicated in Figs, 6 and 6a so that the flesh or skin can round up or extend into the spaces between the outer portions of the teeth and the cutting edges on the opposite sides of the teeth can get right down close to the surface of the skin and give a very close cut or shave it. This makes the cross section of the teeth 3 of general triangular shape as shown in Fig. 6a, giving them good strength and stiffness. The included angle 3a is about 100 to 110 degrees.

It will be seen from the end view of Fig. 2 that when the block I and the elements 2 are assembled they form between this block and the teeth 3 a generally trough shaped passage extending longitudinally for the full length f the cutter head, and which trough or passage is of substantially rectangular cross section. Mounted in this passage is the inner or movable cutter element 8 which is also of general trough-shape or U-shape in cross section, but which section is also rectangular to correspond with the passage. It may be bent up of stock of the desired thickness, or it may be milled from a solid block, and in outside dimensions is substantially the same size as' the longitudinal passage formed by the block l and the side members 2. It has a good sliding tlt in this passage and is guided in its longitudinally reciprocating movement by the walls of the passage. The side walls of this inner element are preferably relieved somewhat as indicated at s leaving longitudinally extending bearing urfaces I0 to thus reduce the friction between this movable element and the side elements 2.

At the upper edges of the side members of the inner cutter 3 it is provided with two series of cutter teeth II extending inwardly therefrom toward each other and inclined at their upper surfaces to correspond with the inclination of the inner walls I2 of the outer teeth 3 and the walls at the base thereof. As these teeth are on the inner side of the outer or stationary cutter teeth 3 it is not necessary that they be tapered to a thin straight edge, but they may be made up of considerable thickness as shown vso as to give them the proper strength and stiffness. The slots between these inner cutter teeth should preferably be carried completely across the upper surface of the cutter member 3 to the outer side edges thereof, but need only break through the major portion of the overhanging portion of the teeth. When the slots are so extended their rear portions act to retain lubricant for oiling the surfaces between the teeth and their outer cutter or guard elements. It is not necessary that there be as many teeth II on the inner or movable cutter as there are teeth 3. As a matter of fact it is preferred that they be only about one-half the number of the outer teeth. It is also preferred that their spacing be not a multiple of the spacing of the outer teeth 3, but vary somewhat therefrom, these inner cutter teeth being as shown in Fig. 3 spaced a different distance slightly greater than the distance between two of the outer cutter teeth 3. Therefore as shown the teeth do not all cut at the same time but cut or come to a cutting position in succession, which greatly reduces the power required to operate the movable cutter and also greatly reduces the liability of the cutter jamming in operation.

It is also preferred that the free ends of the outer cutter or guard teeth 3 overhang or project somewhat beyond the free ends of the inneror movable cutter teeth II as indicated in Figs. 2 and 3, as this reduces the irritation of the skin in the shaving operation. I have found that if the free ends of the inner cutter teeth extend toward the free ends of the outer cutter teeth to a point where the width of the opening or slot between two adjacent outer cutter teeth is about .008 inch wide with the width of the slots about .012 inch at the free ends of the teeth and the slots tapering inwardly somewhat, the spacing is such as to permit easy entrance of the hairs between the teeth for quick shaving, but the skin will not enter suiiiciently to be irritated or injured by the cutters. Thus although the dimensions may vary depending upon the types of beards to be shaved I have found that for general practice the following dimensions are very satisfactory. As indicated in Fig. 6 the slots I3 between the outer cutter or guard teeth 3 taper somewhat, with the width'of the entrance or space a between the outer ends of the teeth preferably equal to about .012 inch, and with the length c of the teeth preferably equal to about .025 inch. The width d of the teeth at their outer ends is preferably about .007 inch. This makes the pitch of the teeth 3 about .019 inch. As indicated above the free ends of the inner cutter teeth II preferably extend to a point where the widths of the slots I3 is about .008 inch. With about this spacing between the outer cutter teeth at the free ends of the inner cutter teeth there is no danger of cutting or irritating the skin. I have found that for the inner cutter teeth II a width of about .010 inch with a gap between them of .030 inch works very satisfactorily, making a pitch for these teeth of about .040 inch. It is preferred that the two sets of cutter teeth and other associated devices be so proportioned and arranged that the dwell at the ends of the reciprocating movement of the inner cutter occurs when the inner cutter teeth I I are under the outer cutter teeth 3. This facilitates entrance of the hairs into cutting position between the teeth because probably these dwells between the movements in opposite directions comprise about of the time, so it can be said that for the greater portion of the time the inner cutter teeth are directly under the outer cutter teeth.

Various means may be employed for operating the inner cutter members but I have shown by way of example an operating element I4 connected to any suitable activator, not shown, for giving it an oscillating or reciprocating movement in a direction indicated by the arrows I5. This device is reduced at its upper end as shown at I8 on which is slidable a sleeve l1 having a tapered free end I 3. rounded on its opposite sides in the direction of movement, and seated in a rectangular opening I9 in the lower wall of the member 8. which opening is alsotapered at itsopposite ends for seating of the tapered rounded end I8 of the member I1. A spring 20 between the member I1 and the shoulder 2I-holds this member I1 seated. in the opening and also holds the movable cutter member 8 against the underside of the outer cutter teeth 3 to maintain them in proper cutting relation. The head may be supported on the activator or casing enclosing it by any suitable means such as spring supports 22 having inturned ends seated in longitudinal transverse notches 23 in the ends of the head.

An important feature of the present construction is an intermediate guard 24 mounted between the two longitudinally extending spaced rows of cutter teeth 3 and II. The side elevation of this element as applied to this particular head is shown in Fig. 4. .It'may be mounted in any suitable manner, but in the present case it has I'a downwardly extending end portion 25 seated in a slot 28 in one endof the mounting block i and to which it is pivoted by a transverse pin 21 in aligned openings in the block and an opening 28 in the portion 25. The other end of the block I is similarly slotted at 29 to receive the downwardly extending portion 38 on the other end of the element 24. This end has a notch 3| extending upwardly from its lower end to receive and seat on a transverse pin 32 in the block I, and to insure a proper fit and seating on this pin and prevent matting of cuttings between the walls of the notch and the pin the upper or inner end of this recess is tapered in opposite directions as indicated at 33 so as to have a line bearing on the pin. The member may also be slotted as indicated at 34 and 3M to give a yielding or spring effect to the parts of the extensions 25 and 3|! to retain them yielding in the block bylfriction and prevent its loosening or rattling. The cutting of the slots causes the walls on opposite sides thereof to spring laterally a small amount out of the plane of the member and` thus frictionally engage the sides of slots 26 and 29 with a yielding spring action. If they do not spring sufficiently they can be given the proper set. At one end it may be provided with a thumbpiece 35 so that the end 30 may be easily lifted upwardly about the pivot 21 for cleaning purposes. The support elements 22 may be slotted as shown at 36, Fig. 9 to accommodate the end portions of this intermediate guard. y

As shown in Fig. 2 the upper free edge of this guard is preferably substantially on a level with the outer surface of the free ends of the outer cutter teeth 3 but by varying this arelation, or that is the elevation of the guard, the closeness of the cut or shave to the surfaceof the skin can be varied. This upper edge of the guard is provided with a series of guard teeth 31 separated by transverse slots in the edge of the guard. For best results these teeth are arranged in alignment with the outer cutter teeth 3 as indicated in Fig. 3, and these teeth are also laterally rounded or curved so as to give a taper as indicated at 38 in Fig. 2. It will be seen that this intermediate guard is spaced from both sets of teeth 3 so as to leave a longitudinal slot between the guard and each of the two rows of cutting teeth to facilitate entrance of the hairs to the proper cutting position. The spacing is such that this intermediate guard 24 prevents gitudinal slot between the tips of the two longitudinal rows of teeth 3. The dimensions of course may vary, but I have found it very satisfactory to have the space between the free ends of the two rows of teeth 3 at about .070 inch with the guard :l about .031 mth thick, and with the lateral taper on the teeth 31 such as to make the widths of the free ends of the teeth about .010 inch. The teeth are made `preferably of about the same thickness as the width of the free ends of the teeth 3 or that is about .007 inch in the example above described. However, after the transverse slots between the teeth 31 are cut they are preferably buied to remove or round oi the sharp edges of the teeth and prevent irritation of the skin. This intermediate guard permits spacing of the two rows of cutter teeth 3 suiliciently to permit free and proper entrance of the hairs between the teeth to cutting position but prevents the skin entering because of this wider spacing to a sufficient extent to be injured. Without this intermediate guard 24 the two rows of cutter teeth have to be set much closer together in order not to irritate the skin. This closer spacing does not permit as free entrance of the hairs to the proper cutting position between the teeth. However, with this intermediate guard the spacing between the two rows of cutter teeth can be made much greater with no danger of injury or irritationto the skin, and this wider spacing permits the hairs to readily enter between the cutter teeth and assume the proper cutting position thus greatly increasing the speed of shaving and giving much better and more efficient operation.

The opposite end portions of the bottom `wall of the inner reciprocating member-8 is slotted at its opposite ends as indicated at 39 to straddle the end portions 25 and 30 -of the inner guard 24, and these slots are preferably made somewhat l wider than the guard so as not to interfere with the skin from blousing or sagging into the lonthe free movement of the inner cutter member. The inner ends ofv these slots are inclined as shown at 40 soas to act as a'sort'of scoop to preventV packing of the cut hairs at the edge of the guard support and the edge of the slot.

It will be seen that with this arrangement the cutter head may be passed in either direction over the surface of the skin in a direction transversely of the head, as indicated by the arrow 4I in Fig. 2, and that it will cut the hairs with equal facility when moving in either direction as it has two complete cutting combinations composed of the outer` or stationary cutter teeth 3 and the inner or movable cutter teeth II cooperating therewith, and as these two rows or sets of cutting means face in opposite directions one of them will always be moving in the proper direction for cutting, that is one' of them will always be moving with the free ends of its teeth moving forwardly. It will also be 4seen that it will ne er be possible to so tilt `thesets of cutters at such a steep angle with respect tothe lsurface f the skin as to cause them -to dig into the skin, because when the surfaces 1 are against the skin this outer surface for one set of cutters will engage the surface of the skin forwardly of the 'other set of cutters t act as a guide and positioning means to determine the angle at which the other set will be positioned with respect to this surface, and therefore the two sets of cutters 3 and I I will automatically be guided and positioned at the proper angle wit'hres'pect to the surface of the skin to secure the best and most rapid cutting operation with minimum irritation to the skin, It will, however, be understood that for best and most rapid cutting operation the parts must be so proportioned and arranged that the hairs can properly enter the spaces between the teeth 3 to the cutting position in the best location forproper cutting. This is secured by means of the intermediate guard 24, which permits the spacing of the free ends of the two sets of cutter teeth 3 at a wider spacing and at such a spacing as to permit free and proper entrance of the hairs into the slots between the teeth 3, but the guard 24 prevents the skin blousing or sagging into the space or longitudinal slot between the ends of the 4two spacedV sets of teeth 3. Thus this combination permits locating the two sets of teeth or cutting elements at the proper spacing to permit rapid and effective cutting of the hairs, but it prevents the skin from entering suiiiciently to be injured or irritated by the cutting elements.

In Figs. 10, 11 and 12 is shown a modification in which the two opposite rows of cutting teeth are the same as that shown in Figs. 1, 2 and 3 except that the intermediate guard 24 is omitted. Therefore the two sets of outer stationary cutter teeth 3 are not spaced as widely as in the form of Figs. 1, 2 and 3, but the slot 64 between them is made narrower so as to prevent the skin from entering too far or from becoming irritated during the shaving operation. 'I'he relative proportions of the stationary cutter teeth and movable cutter teeth Il are the same as in the first form, as are also their relative locations, the only difference being because of theomission of the guard 24 and the narrowing of the spacing slots 64 the mounting block la and the movable cutting element 8a are correspondingly narrowed. The form lwith the intermediate guard is preferred for the reasons above given, but this form without the guard is shown to indicate that the rectangular shape and new assembly of the cutter head is not necessarily confined to use with the intermediate guard.

In Fig. 13 is shown another slight modification the arrangement being the same as that of previously described forms except that the free ends of the outer or stationary guard teeth 3a do not extend to a thin free edge but their free outer ends are thickened somewhat. or that is, are left thicker so that they extend a short distance down over or overlap the free ends of the teeth Il as indicated at 65. 'I'his makes a thicker rounded end for the teeth 3a which obviates any possibility of the teeth digging into the skin or cutting it during the shaving operation. It is also to be understood this form of teeth may be employed in the arrangement of Figs. 1 to 9 and 13 employing the guard-.24 if desired, or with the form of Fig. 1l without the guard. The inner surface 66 may be finished and formed to shape by means of a metal block reciprocated against the outer element and charged with a suitable abrasive compound. In all forms shown the sharp edges and corners of the teeth where they engagel the skin can be polished and rounded by buihng so as to decrease to a minimum danger of irritation.

It is preferred to have teeth or transverse slots in the free edge of the guard 24, but in some cases these teeth may be omitted leaving a smooth surface for contact with the skin. However, this latter construction is not as effective as the toothed or slotted guard.

Having thus set forth the nature of my invention, what I claim is:

1. In a hair cutting device of the character described, a cutter head comprising a body having at one edge two spaced rows of stationary teeth facing in opposite directions with their free ends toward each other, a separate set of cutter teeth cooperating with each row ofl stationary teeth, said two sets of cutter teeth being spaced from each other with the free ends of the teeth in each set directedtoward the other set, a central stationary guard between the free ends of the teeth and spaced therefrom and having spaced projections on its free edge to engage the surface of the skin, and means for reciprocating the inner cutter teeth in a direction transversely of the stationary teeth.

2. In a device of the character described. two spaced cutting devices each comprising a set of spaced stationary outer cutter teeth and a set of movable cutter teeth cooperating therewith, said cutting devices being arranged in opposition to each other and facing in opposite directions with the free ends of the teeth facing each other, an intermediate stationary guard arranged between the cutting devices and spaced therefrom, said guard having spaced projections on its free edge to engage the surface of the skin, and means for reciprocating the inner cutter teeth in a direction transversely of the outer teeth.

3. In a hair cutter, a skin contacting member adapted to pass over the skin for cutting hair therefrom, said member being provided with sets of opposed teeth having free ends extending toward but not reaching each other and separated by slots, a cutter provided with spaced sets of similarly opposed teeth having free ends extending toward each other operating adjacent the member and cooperating therewith to cut hair from the skin as the cutter is passed thereover. and a stationary guard between the sets of teeth and spaced therefrom, said guard having spaced teeth on its free edge to engage the skin as the cutter is passed over said surface.

4. In a cutter head of the character described, a body having a pair of spaced toothed edges arranged with the free ends of the teeth facing each other, a cutter in said body movable relatively thereto and having spaced sets of teeth arranged with the free ends of the teeth facing each other and cooperating with the first teeth for the cutting of hair, and a stationary guard means between said toothed edges and spaced therefrom to prevent the flesh of a user entering therebetween.

5. In a cutter head, a body having a pair of spaced toothed edges forming stationary cutters and arranged with the free ends of the teeth facing each other, a cutter in the body movable relatively thereto and having teeth cooperating with the teeth of said edges for the cutting of hair, a stationary guard between said toothed edges and spaced therefrom and having teeth in alignment with those on the edges, and said guard being in position to prevent the flesh of a user entering between the spaced toothed edges of the body.

6. In a cutter head, a body having a pair of spaced toothed edges arranged with the free ends of the teeth facing each other, a cutter in the body movable relative thereto and having cutter teeth to cooperate with the teeth oi said edges for the cutting of hair, a. guard between said toothed edges and having teeth in alignment with those on said edges, said guard being located to prevent the flesh of a user entering between the spaced toothed edges of the body. said body having slots therein, said guard having legs entering said slots, and means pivoting one of said legs to the body whereby the guard may be swung to an open position to permit cleaning of the cutter head.

7. A cutter head of the character described includinga housing comprising a mounting block and members secured to the opposite sides of the block and having free edge portions extending laterally toward each other, said free edge portions each having a row of stationary cutter teeth with the free ends of the teeth of each row extending toward the other row and spaced from the free ends thereof to provide a longitudinal slot between them, and a substantially rectangular hollow cutter member mounted between said side members for longitudinal reciprocating movement and provided with two longitudinal spaced rows of cutter teeth arranged with the teeth extending in a direction transversely of the slot at the inner surfaces of the stationary teeth and movable transversely thereof to cut hair.

8. A cutter head of the character described comprising a mounting block, side members in the form of plates secured to the opposite sides of the block and extending laterally therefrom, the free edges of said plates being directed inwardly toward each other and each provided with a set of stationary cutter'teeth with the free ends of each set directed toward the other set and spaced therefrom, and a hollow movable cutter member of general rectangular shape mounted to reciprocate between said side members and having bearing thereon, the free edge portions of the sides of the movable member being directed inwardly toward each other and spaced therefrom. and each having a row of cutter teeth at the inner surfaces of a row of stationary cutter teeth and extending in the same direction as the stationary teeth and movable transversely thereof to cooperate with said teeth for cutting hair.

9. In a hair cutter, a skin contacting member adapted to pass over the skin for cutting hair therefrom, said member being provided with sets of opposed teeth having free ends extending toward but not reaching each other and separated by slots, a cutter provided with spaced sets of similarly opposed teeth having free ends extending toward each other operating adjacent the member and cooperating therewith to cut hair from the skin as the cutter is passed thereover, and a stationary guard between the sets of teeth and spaced therefrom to engage the skin as the cutter is passed over its surface.

10. A cutter head of the character described including a housing having free edge portions extending laterally toward each other and theirouter surfaces comprising a pair of substantially at skin contacting surfaces inclined in opposite directions backwardly from the center, said free edge portions each having a row of stationary cutter teeth with the free ends of the teeth of each row extending toward the other row and spaced from the free ends thereof to provide a longitudinal slot between them, and a substantially rectangular hollow cutter member mounted in said housing for longitudinal reciprocating movement and provided with two longitudinal spaced rows of cutter teeth arranged with the teeth extending in a direction transversely of the slot at the inner surfaces of the stationary teeth and movable transversely thereof to cut hair.

1l. A cutter head of the character described comprising a mounting member, side members in the form of plates secured to the opposite sides of the mounting member and extending laterally therefrom, the free edge portions of said plates being directed inwardly toward each other and having a pair of oppositely inclined substantially at skin contacting surfaces inclined backwardly from the opposed free edges thereof, said free edges each provided with a set of stationary cutter teeth with the free ends of each set directed toward the other set and spaced therefrom, and a hollow movable cutter member having flat surfaces to bear on the side members and mounted to reciprocate between said side members, the free edge portions of the sides of the movable member being directed inward toward each other and spaced therefrom and each having a row of cutter teeth at the inner surfaces of a row of stationary cutter teeth and extending in the same direction as the stationary teeth and movable transversely thereof to cooperate with said teeth for cutting hair.

l2. A cutter head of the character described comprising a mounting member, side members in the form of plates secured to the opposite sides of the mounting member and extending laterally therefrom, the free edges of said plates being directed inwardly toward each other and each provided with a set of stationary cutter teeth with the free ends of each set directed toward the other set and spaced therefrom, and a hollow movable cutter member having ilat surfaces to bear on the side members and mounted to reciprocate between said side members, the free edge portions of thesides of the movable members being directed inwardly toward each other and spaced therefrom and each having a row of cutter teeth at the inner surfaces'of a row of stationary cutter teeth and extending in the same direction as the stationary teeth and movable transversely thereof to cooperate with said teeth for cutting hair.

'THOMAS J. MURPHY. 

